MAINTAINERS: Add entry for LED devices documentation

When given patches that only touch documentation directory for LED
devices (Documentation/leds/), get_maintainer doesn't list mailing list
for LED subsystem. However, the patch should be seen on that list in order
to be applied.

Add the entry for Documentation/leds/.
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230319084604.19749-1-bagasdotme@gmail.com

MAINTAINERS

@@ -11648,6 +11648,7 @@ L:	linux-leds@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-leds.git
 F:	Documentation/devicetree/bindings/leds/
+F:	Documentation/leds/
 F:	drivers/leds/
 F:	include/dt-bindings/leds/
 F:	include/linux/leds.h